Kiwifruit variety named &#39;Bruce&#39;

ABSTRACT

A new and distinct kiwifruit variety is described. The variety results from selection among a population of seedlings derived from a controlled pollination crossing the kiwifruit varieties known as ‘Hort16A’ (U.S. Plant Pat. No. 11,066) and an unreleased selection CK39_16 (not patented). The new variety is a male plant which flowers in a period well-synchronized for pollination of the female variety ‘Hort16A’ (U.S. Plant Pat. No. 11,066). The new variety is characterized by the timing of flowering, distinctive red/brown hairs evident on young shoots and the underside of young leaves. The new variety appears suitable for use as a pollinizer in commercial kiwifruit production and has been named ‘Bruce’.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/134,476, filed Jul. 9, 2008, the entire contents of which are incorporated herein by reference and should be considered a part of this specification.

BACKGROUND AND SUMMARY OF THE INVENTION

Kiwi plants in cultivation are mainly varieties of A. deliciosa, particularly ‘Hayward’ although some A. chinensis and A. arguta varieties are grown. A. deliciosa and A. chinensis are closely related and varieties of both types have large fruit (˜100 g) with hair on the skin. The main varieties in New Zealand are ‘Hayward’ (A. deliciosa) and ‘Hort16A’ (A. chinensis). Fruit are usually cut and eaten with a spoon.

All Actinidia species are dioecious, so female varieties have to be interplanted with male pollinizers to ensure fruit production.

A. chinensis vines are deciduous and tend to grow vigorously in spring and summer when rapidly-growing shoots can intertwine and tangle if not managed. Vines do best in a mild warm-temperate climate without late spring or early autumn frosts. They produce consistently heavy crops when grown in well-drained fertile soils and given regular irrigation in dry spells.

A. chinensis flowers in the spring (mid October-early December) in New Zealand. Harvest of A. chinensis fruit may occur between April and late-May in New Zealand depending on the selection and location of plantings.

Efficient pollination of female kiwifruit varieties influences seed numbers, which in turn influences fruit size and dry matter. In selecting new kiwifruit pollinizers the focus is on traits to enhance efficient pollination including pollen viability, pollen yield, number of flowers produced, and synchronization of the release of pollen from male flowers at the same time as the female flowers are receptive. A low vigor cultivar is preferred to minimize pruning costs.

The new variety was selected from a population of seedlings derived from a controlled pollination crossing of the kiwifruit varieties known as ‘Hort16A’ (U.S. Plant Pat. No. 11,066) and an unreleased selection CK39_(—)16 (not patented) after observations of character and performance carried out from 1999 to 2000. The patented female parent ‘Hort16A’ was bred and selected in New Zealand, U.S. Plant Pat. No. 11,066. The unpatented male parent CK39_(—)16 was selected in New Zealand from seedling plants raised from an introduction of open-pollinated seed from an un-patented parent from China in 1989. This new variety was created during the course of a planned plant-breeding program, which was initiated during 1995 in Te Puke, New Zealand. The cross was made on Oct. 29, 1995 in Te Puke, New Zealand. Seeds were sown in the spring of 1996 and 80 seedlings from this cross were planted out in the field at Te Puke in 1997. The selection ‘Bruce’ first flowered in October 2000. Selection ‘Bruce’ was grafted in 2000 onto five existing kiwifruit rootstocks at Te Puke, in a clonal selection trial plot, using graft wood from the original seedling plant.

The new variety was selected from among plants located on land controlled by the Horticulture and Food Research Institute of New Zealand Limited at Te Puke, New Zealand, and was assigned the breeder code, 32-01-13a. The new variety has since been named ‘Bruce’.

The present invention is a new and distinctive kiwifruit male variety whose flowering period coincides well with the patented female kiwifruit plant ‘Hort16A’ in most districts where kiwifruit are grown in New Zealand.

The new variety can be asexually reproduced as cuttings or by grafting or budding on to seedling or cutting-grown rootstocks of A. deliciosa or A. chinensis. Trial plantings of grafted plants established at the Te Puke, Nelson and Kerikeri Research Centres in 2003 have shown that the unique combination of characters come true to form and are established and transmitted through succeeding asexual propagations.

The new variety is characterized as follows:

Plant ploidy: diploid.

Plant form and vigor: a twining habit, with strong vigor, similar to ‘Hort16A’ (U.S. Plant Pat. No. 11,066); the surface of the dormant cane is smooth and a white bloom is present; distinctive red/brown hairs are evident on the young shoots and the underside of young leaves.

Foliage: the mature leaf is broad ovate in shape; the upper surface of the leaf is smooth; the lobes of a mature leaf are arranged slightly overlapping.

Flower: the number of flowers in each inflorescence is typically between one to four flowers, with each inflorescence comprising a single king flower and one or two side flowers; the single colored petal is absent of any red blotch which is sometime present on the petals of flowers of other male varieties, for example ‘Meteor’ (not patented).

Time of flowering: early.

Plant health: no visible leaf symptoms have been observed indicating the plant is not virus-infected. Resistance to pests and disease is unknown.

Pollination efficiency: the new variety was initially selected on the basis of its potential for synchrony of flowering with the commercially important New Zealand female kiwifruit variety ‘Hort16A’ (U.S. Plant Pat. No. 11,066) and the resulting large fruit size of fruit of ‘Hort16A’ (U.S. Plant Pat. No. 11,066) after hand pollination with excess pollen. Subsequent trials indicate that flowering of the new variety does appear to be well synchronized with when female flowers of the variety ‘Hort16A’ (U.S. Plant Pat. No. 11,066) are receptive in many production areas in New Zealand. Observations of the performance of the new variety indicate it has potential to bring about improved yield from ‘Hort16A’ (U.S. Plant Pat. No. 11,066) relative to other male pollinizers currently used commercially in New Zealand such as ‘Meteor’ (not patented) and ‘Sparkler’ (not patented) due to better coincidence with ‘Hort16A’ (U.S. Plant Pat. No. 11,066) flowering, and good ability to influence fruit size when pollen is delivered to the female flowers. Key attributes of the new variety in this regard include good pollen viability, and a high pollen yield, in combination with a medium flower load per plant (measured as the number of flowers per meter cane).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures show typical specimens of the plant, foliage, and flowers of the new variety as depicted in colors as nearly true as is reasonably possible in a color representation of this type.

FIG. 1 shows a plant of the variety ‘Bruce’ in the field; view is of flower buds, open flowers, and new leaves.

FIG. 2 shows an inflorescence of the variety ‘Bruce’; view is of flower buds, open flowers, and pedicel.

FIG. 3 shows the tip of a new shoot of the plant of the variety ‘Bruce’; view shows the typical red coloration on the young shoot of ‘Bruce’.

FIG. 4 shows a fully expanded leaf of the plant of the variety ‘Bruce’.

FIG. 5 shows a typical vine of the variety ‘Bruce’.

FIG. 6 shows typical flowers and buds of the variety ‘Bruce’.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of the new variety. The new diploid kiwifruit variety ‘Bruce’ is staminate (male), produces only male flowers, and no fruit.

Horticultural terminology is used in accordance with UPOV guidelines for kiwi. All dimensions are in millimeters, and all weights are in grams (unless otherwise stated). Certain characteristics of this variety, such as growth and color, may change with changing environmental conditions (e.g., light, temperature, moisture), nutrient availability, rootstocks, or other factors. Color descriptions and other terminology are used in accordance with their ordinary dictionary descriptions, unless the context clearly indicates otherwise. Color names beginning with a capital letter designate values based upon the R.H.S. Colour Chart published by The Royal Horticultural Society, London, England.

TABLE OF CHARACTERISTICS ‘Bruce’ PLANT (Measurements from samples of 10, unless stated otherwise) Plant: sex expression Male Plant: ploidy Diploid Plant: vigour Vigorous Young shoot: hairs Present Young shoot: density of hairs Dense Young shoot: type of hairs Tomentose Young shoot: anthocyanin coloration of growing tip Medium Young shoot: anthocyanin coloration of leaf axil Present STEM Stem: coloration of leaf axil Absent or very weak Stem: diameter Mean: 10.58 mm, Range: 8.7 mm-13.8 mm Stem: length 1.2-2.0 mm Stem: dormant bud diameter Mean: 7.96 mm, Range: 6.9 mm-9.9 mm Stem: color on upper side of dormant shoot Grey-brown, R.H.S. 200C Stem: character of bark Smooth Stem: hairs Present Stem: conspicuousness of lenticels Conspicuous Stem: number of lenticels/cm² bark Mean: 4.0 lenticels, Range: 2.5-5.4 lenticels Stem: color of lenticels Orange-brown, R.H.S. 177C Stem: size of lenticels-length Mean: 2.34 mm, Range: 1.3 mm-3.5 mm Stem size of lenticels-maximum width Mean: 1.67 mm, Range: 0.71 mm-2.08 mm Stem size of bud support Mean: 4.9 mm, Range: 4.0 mm-5.9 mm Stem: visibility of bud (dormant canes) Visible Stem: number of hairs visible on bud (dormant Many canes) Stem: presence of pith Present Stem: type of pith Lamellate LEAF (Mature) Leaf: general shape of blade Very broad ovate Leaf: length Mean: 144 mm, Range: 124 mm-164 mm Leaf: width Mean: 161 mm, Range: 138-185 mm Leaf: petiole length Mean: 158 mm, Range: 90-192 mm Leaf: ratio leaf length to width 0.90 Leaf: ratio leaf length to petiole length 0.91 Leaf: shape of tip of blade Acute Leaf: shape of base of blade Cordate Leaf: arrangement of leaf bases Slightly overlapping Leaf: puckering/blistering on upper side of blade Weak Leaf: margin Ciliate Leaf: green color of upper side of blade Medium green, R.H.S. 137A Leaf: glossiness of upper surface of blade Medium glossy Leaf: color of lower side of blade Light green, R.H.S. 137C Leaf: glaucosity (lower side of blade) Absent Leaf: hairs on petiole Present Leaf: density of hairs on petiole Dense Leaf: anthocyanin coloration on upper side of Weak petiole FLOWER Inflorescence: predominant number of flowers 3 Flower: pedicel hairs Present Flower: pedicel, length of hairs Very short Flower: pedicel length Mean: 36.7 mm, Range: 30.3 mm-45.2 mm Flower: number of sepals 5 to 7 Flower: color of sepals Yellow-green, R.H.S. 195A/147C Flower: length of sepals Mean: 6.23 mm, Range: 5.08 mm-7.65 mm Flower: diameter of sepals Mean: 4.65 mm, Range: 3.69 mm-6.01 mm Flower: diameter (terminal or king flower when fully Mean: 36.2 mm, Range: 25.3 mm-40.7 mm open) Flower: mean number of petals per flower Mean: 6.8 petals, Range: 5-9 petals Flower: length of petals Mean: 16.43 mm, Range: 14.5 mm-18.0 mm Flower: width of petals Mean: 15.24 mm, Range: 12.8 mm-18.1 mm Flower: ratio petal length/width 1.15 Flower: arrangement of petals Overlapping Flower: petal curvature of apex Strongly expressed Flower: primary color of petals (when fully open) White, R.H.S. 158D Flower: type of coloration of petals Bi-color Flower: secondary color of base of petals. Green, R.H.S. 146D Flower: filament color Greenish-white, R.H.S. 157A Flower: anther color Yellow/orange, R.H.S. 163A Flower. anther number per flower Mean. 52.2 anthers, Range. 37-68 anthers EVENTS Time of vegetative budbreak Early-similar to Hort16A female Time of beginning of flowering Early-similar to Hort16A female

Observations were made on plants grown at Te Puke, New Zealand. These plants had been grafted on to seedling kiwifruit rootstocks.

-   Rootstocks: ‘Bruce’ vines can be grown on the same rootstocks as can     ‘Hort16A’. Rootstocks currently being used in New Zealand include A.     deliciosa and A. chinensis seedlings, ‘Hayward’ (not patented) and     ‘Kaimai’ (not patented) rooted cuttings. -   Flowering and plant management: Young vines of ‘Bruce’ flower     heavily when young, and most flowers should be removed from grafts     and young plants to allow the plant to establish a good canopy of     canes. Mature plants can be pruned after flowering by removing up to     two thirds of the canopy and allowing new canes to establish over     the growing period. Minimal pruning is done in winter. -   Pest and disease resistance/susceptibility: Pest and disease issues     are of minor significance for non-cropping pollinizers, and at this     stage we have not recorded any particular susceptibilities to pests     or diseases for this male variety. -   Comparison to closest cultivar The distinctive characteristics of     this new kiwifruit variety, described in detail below, were observed     in 2007 at Te Puke, New Zealand. The age of the plants was 7 years     from grafting onto seedling rootstocks. Comparison with similar male     varieties, ‘Meteor’ and ‘Sparkler’, in commercial use in New Zealand     shows that ‘Bruce’ can be distinguished from these varieties as     outlined in Table 1.

TABLE 1 COMPARISON WITH SIMILAR VARIETIES Characteristic Bruce Meteor Sparkler Flower: Petal color Absent Present Absent blotch presence Surface of dormant Smooth Rough Smooth cane Color of hairs on young Red/Brown Pale Brown Pale red shoots and leaves White bloom on Present, medium Not present or weak Present, strong dormant cane expression expression Upper surface of leaf to Smooth Rough Smooth the touch Mature leaf lobe Slightly overlapping Overlapping Touching arrangement Time of flowering in Starts at same time as Starts up to 10 days Starts from 2-7 days relation to ‘Hort16A’ ‘Hort16A’ before ‘Hort16A’ after ‘Hort16A’ female

‘Meteor’ and ‘Bruce’ are relatively easy to distinguish in that ‘Meteor’ has a rough surface of canes and upper surface of leaves, has a pink blotch on petals at time of flowering and weak expression of white bloom on dormant canes, whereas ‘Bruce’ has smooth leaves and canes, no pink blotch on flowers and medium expression of white bloom on dormant canes. ‘Sparkler’ and ‘Bruce’ are more similar in appearance overall as both have smooth leaves and canes, but ‘Sparkler’ commences flowering up to 7 days later than ‘Bruce’ and the young flowering shoots of ‘Bruce’ and the undersides of young leaves have a much more intense red color compared to ‘Sparkler’. In addition, ‘Bruce’ leaf lobes are slightly overlapping, while ‘Sparkler’ leaf lobes are touching. 

1. A new and distinct kiwifruit variety as herein described and illustrated, selected from seedlings derived from a controlled pollination crossing of the kiwifruit varieties known as ‘Hort16A’ (U.S. Plant Pat. No. 11,066) and an unreleased selection CK39_(—)16 (not patented) and characterized by its appearance and flowering period. 